Adopted woman discovers long-lost sister was living next door

A US woman has learnt the sister she had never met was living over the fence for months.

Hillary Harris, 31, discovered through adoption records in 2012 she had a half-sibling named Dawn Johnson, Good Morning Americareports.

The two women shared the same birth father, Wayne Clouse, whose obituary provided Ms Harris with a vital clue to Ms Johnson’s location.

The pair with Ms Harris' daughter, Stella. (GMA) (9NEWS)

“I learned (Johnson) was from Greenwood, Wisconsin, and was the Loyal Corn Festival Queen in the 1980s,” she told GMA.

Despite her relentless search efforts, it wasn’t until five years later when Ms Harris had a breakthrough; her husband told her a woman named Dawn from Greenwood had moved in next door to their home in the city of Eau Claire.

The 31-year-old said she “immediately” had a suspicion her new neighbour was more than that.

The sisters said they couldn't imagine like one another now. (GMA) (GMA)

In a text message, Ms Harris asked Ms Johnson, 50, about her birth father, and it soon became apparent the pair were in fact family.